Evaluation of DNA methylation status at differentially methylated regions in IVF-conceived newborn twins

Objective: To examine the effect of assisted reproductive technology on the stability of DNA methylation at differentially methylated regions (DMRs) in twins conceived by IVF. Design: Prospective clinical observational study. Setting: IVF center, university-affiliated teaching hospital. Patient(s): Fifty-nine pairs of twins were recruited, including 29 pairs conceived through IVF and 30 pairs of naturally conceived twins. Intervention(s): Collection of umbilical cord blood samples. Main Outcome Measure(s): DNA was extracted from umbilical cord blood. Two maternally methylated regions (KvDMR1 and PEG1) and one paternally methylated region (H19/IGF2 DMR) were analyzed using bisulfite-based technologies. Result(s): Although H19/IGF2 DMR and KvDMR1 showed slightly more variable levels of methylation in IVF cases than in spontaneous cases, methylation indices did not reveal significant differences at three DMRs between IVF-conceived and naturally conceived twins. Conclusion(s): Our results suggest no significant increase in imprint variability at these DMRs, but the greater variance in the IVF twins has a biologically meaningful consequence and may be a topic for future investigation. Large cohorts are needed to systematically assess the potential epigenetic risk in twins conceived with IVF. (Fertil Steril (R) 2011; 95:1975-9. (C) 2011 by American Society for Reproductive Medicine.)